Inexpensive and easily replicable precipitation of CuO nanoparticles for low temperature carbon monoxide and toluene catalytic oxidation

Herein CuO nanoparticles (NPs) with nanostructures were prepared by precipitation method using hydrate copper sulfate (CuSO4.5H2O) and sodium hydroxide followed by heat treatment at 400 °C. The as-prepared CuO NPs with nanostructures were investigated using X-ray diffraction (XRD), Fourier Transformed Infra-red spectroscopy (FTIR), Raman spectroscopy, Scanning electron microscopy (SEM), X-ray photochemical spectroscopy (XPS), Energy dispersive spectroscopy (EDS), and Ultra-violet-visible (UV-vis) spectroscopy. In order to evaluate the reducibility, temperature programmed reduction (H2-TPR) was applied. More importantly, CuO NPs was successfully tested as catalyst towards the total conversion of carbon monoxide (CO) and toluene (C7H8). Both XRD and Raman analysis as well as FTIR show that the sample exhibited a monoclinic spinel structure. SEM images indicate that CuO NPs are well-covered by grains size exhibiting homogeneous morphology composed of very fine interconnected particles with an apparent porosity. The sample was made up of Cu and O, according to the XPS and EDS measurements. The band gap energy obtained from optical property analysis is ∼2.65 eV. The catalytic performances of CuO NPs can be assigned to the combined effects of crystal structure, morphology, surface oxygen mobility, redox property and the higher specific surface area (∼87 m2/g). More precisely XPS and H2-TPR data suggests that, the conversion of CO and C7H8 over CuO NPs follows a Mars-van Krevelen type mechanism. More importantly CuO NPs catalysts is reusable and exhibited good stability in the prolonged isothermal test. Thus, CuO NPs is confirmed as an efficient and inexpensive catalysts for CO and C7H8 conversion at low temperatures.